Bug 179953 – [WinCairo] DumpRenderTree displays error message in the beginning

• Status: RESOLVED
• Resolution: WONTFIX
• Component: Tools / Tests

[Basuke Suzuki]

> Cannot create EGL surfaceless context: missing EGL_KHR_surfaceless_{context,opengl} extension.

I couldn't find out which commit starts causing this error, but at least I saw this one in the commit 472a67c6c2fc549c499744a225fcd5fb68528765.

[Basuke Suzuki]

You can see this error not launching entire layout tests, but by directly launch command simply typing like this: 

> .\WebKitBuild\Release\bin64\DumpRenderTree.exe - "LayoutTests\\accessibility\\input-image-alt.html'--timeout'300"

[Fujii Hironori]

(In reply to Basuke Suzuki from comment #0)
> > Cannot create EGL surfaceless context: missing EGL_KHR_surfaceless_{context,opengl} extension.
> 
> I couldn't find out which commit starts causing this error, but at least I
> saw this one in the commit 472a67c6c2fc549c499744a225fcd5fb68528765.

Bug 178937 has added this message.

[Basuke Suzuki]

Thanks!

[Tomoki Imai]

The error message is harmless.

When webkit creates sharing OpenGL context,
1. it tries to create surfaceless context, 
2. if surfaceless context is not supported then create pixel buffer and its context.

In WinCairo, surfaceless context is not supported by ANGLE, so it outputs error message.
But it creates pixel buffer and the context, then uses it as sharing OpenGL Context.  

You can see the actual code in GLContextEGL::createSharingContext (/Source/WebCore/platform/graphics/egl/GLContextEGL.cpp).